1. Technical Field of the Invention
The invention relates generally to communication systems; and, more particularly, it relates to management and allocation of the available communication resources and functionality within communication systems.
2. Description of Related Art
Data communication systems have been under continual development for many years. In recent years, WPANs (Wireless Personal Area Networks) have been under increasing development. A WPAN may be viewed as a network that is established when two or more devices connect to support communication of data between themselves in an area having a radius of up to approximately 10 meters. Typically, earlier implementations of WPANs include a central PNC (piconet coordinator) or a “master” that governs the communication of all of the other communication devices within the WPAN. Although some more recent designs of WPANs focus more particularly distributed control of the network management and communication between the various devices therein. Also, any of the communication devices within such a WPAN is typically capable of operating as the PNC.
As is known, the Bluetooth® communication standard is the first such PAN (Personal Area Network) communication standard that has been developed. In accordance with the Bluetooth® communication standard, the communication between the various devices in such a WPAN is strictly performed using an M/S (Master/Slave) configuration. Each of the devices within such a Bluetooth® WPAN is M/S capable. Typically one of the devices or a first device within the Bluetooth® WPAN, transmits a beacon signal (or an access invitation signal) while operating as the “master” device of the Bluetooth® WPAN to the other “slave” devices of the Bluetooth® WPAN. In other words, the “master” device of the Bluetooth® WPAN polls the other “slave” devices to get them to respond.
However, other WPANs may be implemented such that the devices do not operate according to such an M/S (Master/Slave) type relationship. Typically, some of the communication devices within the WPAN are designated and operate as PNCs, and some of the communication devices are designated and operate as DEVs. The PNCs operate to coordinate the communication between themselves and the DEVs within the WPAN. Sometimes, such a PNC may be implemented to operate as a master with respect to the 1 or more DEVs that operate as slaves, but this need not be the case in all instances—the strict M/S relationship is typically the case only in a Bluetooth® WPAN.
In even some other instances, two or more Bluetooth® piconets operate cooperatively such that they communicate via the masters of the two or more corresponding Bluetooth® piconets. For example, in a scatternet, a single DEV may interact with two or more masters. This implementation will allow various devices within different piconets that are located relatively far from one another to communicate with one another via the masters of their corresponding piconets. However, within a scatternet implementation, a problem may arise such that each of the individual piconets must be able to operate in relative close proximity with other piconets without interfering with one another. This inherently requires a great deal of synchronization between the piconets, which may be very difficult to achieve in some instances. It is also noted that independently operating piconets, not implemented within a scatternet implementation, may also suffer from deleterious effects of interference with other piconets located within relative close proximity.
Some PAN communication standards and recommended practices have been developed (and some are still being developed) by the IEEE (Institute of Electrical & Electronics Engineers) 802.15 working group. These standards and recommended practices may generally be referred to as being provided under the umbrella of the IEEE 802.15 working group. Perhaps the most common standard is the IEEE 802.15.1 standard which adopts the core of Bluetooth® specification and which generally can support an operational rate of 1 Mbps (Mega-bits per second).
The IEEE 802.15.2 recommended practice specification has been developed primarily in an effort to support the co-existence of the IEEE 802.15.1 Bluetooth® core with IEEE 802.11b and IEEE 802.11g WLANs (Wireless Local Area Networks). As some examples of the pertinent frequency spectra of concern, the IEEE 802.11b and IEEE 802.11g WLAN (Wireless Local Area Network) standards both operate within the approximate 2.4 GHz frequency range. The IEEE 802.11a WLAN standard operates within the approximate 5 GHz frequency range. This IEEE 802.15.2 recommended practice specification has been developed to ensure that such a WLAN and a Bluetooth® piconet may operate simultaneously within relatively close proximity of one another without significant interference with one another.
In addition, the IEEE 802.15.3 high data rate PAN standard has been developed in an effort to support operational rates up to approximately 55 Mbps. In this IEEE 802.15.3 standard, the PNCs and DEVs do not operate according to an M/S relationship as they do according to Bluetooth R. In contradistinction, a PNC operates similarly to an AP (Access Point) and manages the various DEVs such that they are guaranteed to perform their respective communication according to their appropriate time slots thereby ensuring proper performance and operation within the piconet. An extension (currently under progress) of the IEEE 802.15.3 high data rate PAN standard is the IEEE 802.15.3 WPAN (Wireless Personal Area Network) High Rate Alternative PHY Task Group 3a (TG3a). This is sometimes referred to the IEEE 802.15.3a extended high data rate PAN standard, and it can support operational rates up to 480 Mbps.
Yet another standard developed by the IEEE 802.15 working group is the IEEE 802.15.4 low data rate PAN standard that generally supports data rates within the range of approximately 10 kbps (kilo-bits per second) and 250 kbps.
Referring to the IEEE 802.11 standards, it has been under continual development in an effort to try to improve the way in which WLANs operate. In this particular effort, there have been a number of amendments to the IEEE 802.11 standard, initially starting with the 802.11a standard, and then also including the commonly known 802.11b standard and an even newer amendment, namely, the 802.11g standard. The 802.11g standard is backward compatible with the 802.11b standard, so that legacy devices within the WLAN can still interact with the WLAN, although 802.11g operable devices operating within an 802.11b WLAN typically employ a reduced functionality set.
There are typically two manners that are known in the art by which a WLAN may be implemented: ad hoc (shown in FIG. 1A) and infrastructure (shown in FIG. 1B).
FIG. 1A is a system diagram illustrating a prior art ad hoc WLAN (Wireless Local Area Network) communication system. Referring to FIG. 1A, the ad hoc implementation employs a number of WLAN interactive devices that are typically operable to communicate with each of the other WLAN interactive devices within the WLAN. There is oftentimes no regimented or organized structure to the network. In some instances, one of the WLAN interactive devices is designated as a master of the network and the other WLAN interactive devices operate as slaves with respect to that master.
FIG. 1B is a system diagram illustrating a prior art infrastructure/multiple AP (Access Point) WLAN communication system. Referring now to the FIG. 1B, in the infrastructure (or multiple AP) WLAN, a number of APs are employed to support communication with the WLAN interactive devices (which are sometimes referred to as STAs (wireless STAtions) in the infrastructure implementation). This infrastructure architecture uses fixed network APs with which the STAs can communicate. These network APs are sometimes connected to landlines (that may be connected to one or more WANs (Wide Area Networks)) to widen the communication system's capability by bridging wireless nodes to other wired nodes. If service areas overlap, handoffs can occur. This infrastructure structure may be implemented in a manner that is analogous to the present day cellular networks around the world.
Considering the various 802.11 standards, the IEEE 802.11g standard extends the data rates for packet transmission in the 2.4 GHz (Giga-Hertz) frequency band. This is achieved by allowing packets, also known as frames, of two distinct types to coexist in this band. Frames utilizing DSSS/CCK (Direct Sequence Spread Spectrum with Complementary Code Keying) modulation have been specified for transmission in the 2.4 GHz band at rates up to 11 Mbps (Mega-bits per second) as part of the 802.11b standard. The 802.11a standard uses a different frame format with OFDM (Orthogonal Frequency Division Multiplexing) modulation to transmit at rates up to 54 Mbps (Mega-bits per second) with carrier frequencies in the 5 GHz band. The 802.11g standard allows for such OFDM frames to coexist with DSSS/CCK frames at 2.4 GHz. However, the properties of these two different types of frames, as well as their processing at an 802.11g receiver, are very different. Also, this portion of the frequency spectrum is unlicensed, so there are many other non-packet signals present in this band which should be ignored by an 802.11g receiver. In general, there are a variety of ways in which the communications may be supported under the umbrella of the IEEE 802.11 standards.
In the current state of the art, the standards generated by the IEEE 802.15 working group and the IEEE 802.11 standards are separate and distinct in operation with no overlap with one another. A primary design directive of the various communication protocols associated with these standards is to allow their co-existence without interacting and/or interfering with one another. Within the prior art, those communication systems and devices included therein that employ any of the standards generated by the IEEE 802.15 working group exclusively employ a standard generated by the IEEE 802.15 working group, and those communication systems and devices included therein that employ any of the IEEE 802.11 related standards exclusively employ an IEEE 802.11 related standard.